How bad would a Euro-spec A6M Zero be?

[Admiral Beez]

Assuming it's stuck with the Nakajima Sakae variants of the time, had the Zero been launched in summer 1940 with the addition of pilot armour, self sealing fuel tanks and a working radio would it have been uncompetitive against the Allied fighters of 1940-1942?

Instead of a Wiki-reported empty and gross weight of 3,704 lb and 6,164 lb, the weight would be closer to other radial fighters of the time, like the Bloch or Curtiss Hawk. Mind you, I don't believe these early Allied radial fighters had self sealing tanks until later.

 

[Thumpalumpacus]

We're talking, what, around 1,000 lbs of additional weight? I imagine it'd have an impact on time-to-climb and immediate climb, range, and turn as well. I'm not knowledgeable enough to give specific numbers.

I don't know that it'd be bad, but I suspect it would make it less and not more feasible for any hypothetical ETO ops. It would reduce the plane's strong-points of maneuverability and range while reducing performance, which was already average outside of those two parameters.

 

[Admiral Beez]

We're talking, what, around 1,000 lbs of additional weight? I imagine it'd have an impact on time-to-climb and immediate climb, range, and turn as well. I'm not knowledgeable enough to give specific numbers.

I don't know that it'd be bad, but I suspect it would make it less and not more feasible for any hypothetical ETO ops. It would reduce the plane's strong-points of maneuverability and range while reducing performance, which was already average outside of those two parameters.

Oh, let's not look at ETO fantasy ops. But we can definitely consider changes in PTO.

 

[Thumpalumpacus]

Oh, let's not look at ETO fantasy ops. But we can definitely consider changes in PTO.

PTO only, I don't think those changes would really hamper (pun intended) the Zero against F4Fs; the performance margin was enough to absorb them. F4F pilots would likely still have to team up and weave. They could perhaps gain a little in relative performance, but I don't think the mods you're suggesting would make the Zero unsuitable in PTO.

Hopefully someone with engineering/aerospace knowledge can put numbers to your suggestions. I can't.

 

[Admiral Beez]

PTO only, I don't think those changes would really hamper (pun intended) the Zero against F4Fs; the performance margin was enough to absorb them. F4F pilots would likely still have to team up and weave. They could perhaps gain a little in relative performance, but I don't think the mods you're suggesting would make the Zero unsuitable in PTO.

Hopefully someone with engineering/aerospace knowledge can put numbers to your suggestions. I can't.

Of the three; armour, self sealing tanks, and working radios (the OEM units were removed due to failure and to save weight), which would be most useful?

 

[Thumpalumpacus]

Of the three; armour, self sealing tanks, and working radios (the OEM units were removed due to failure and to save weight), which would be most useful?

Radios, SSFTs, and armor, in that order, jmo, yymv, etc.

 

[SaparotRob]

IMHO In this order:
1. Working radios. Those IJN pilots were the most trained and experienced in the Theatre. I've read that they were skilled in aerobatics and were equipped with a fine aerobatic plane. If those guys could communicate and coordinate their CAP, attack, escort and CAP missions, I'm sure the the Allied learning curve about the Zero would've taken longer and have cost more lives. The IJN pilots might have lived a little longer as well. "Hoshi! Watch your six!" Those guys were really good. I'm sure they would have had excellent radio discipline. And they could have coordinated there CAP screens as well.

2. Self sealing tanks. What I've read most about the PTO was the Zero would burst into flames when hit. Always followed up with; American aircraft being equipped with s/s tanks.

3. Armor. I don't think those guys would have gone for it.

 

[Admiral Beez]

3. Armor. I don't think those guys would have gone for it.

Great post. On Armour, the IJN's brothers in the IJAF got armour for their fighters in the Kawasaki Ki-61 and the late-war Ki-84.

The IJN guys also got armour in their land based Kawanishi N1K. At least I think so, as I don't see any armour behind the pilot's seat here.

 

[ThomasP]

Some versions of the A6M5 were fitted with pilot seat armour.

N1K-1/-2 were fitted with pilot seat armour, BP windshield, and SSFT or CO2 fire extinguisher system.

 

[Admiral Beez]

How do our heavier but protected Zeros compare against Spitfires over Darwin?

http://darwinspitfires.com/index.php?page=spitfire-vc-versus-the-zero

And what of the Zero's superlative endurance? In addition to armour, self sealing tanks are heavier and by their nature carry less fuel.

 

[Glider]

Some observations

a) We know that the A6M3 was superior in almost every way to the Spit V so the basic premise of the thread How bad would a Euro spec A6M be I disagree with, as both versions were common in 1942 and the Zero was best. With that in mind I don't see why an A6M2 wouldn't have the advantage over any earlier Spitfire.

b) Compared to the Me109, my suspicion is that the 109 wouldn't have been at such a disadvantage. It had a much better initial dive which means that given altitude, the 109 had an easy escape route.

c) Against the Fw190, the 190 has all the advantages as long of course, as they avoid dogfighting. That shouldn't be held against the Zero, as in 1941 early 42 the Fw 190 was the best fighter by some margin, anywhere.

c) Later Japanese fighters did have a level of protection but normally nowhere near as much as other nations

 

[Shortround6]

We know that the A6M3 was superior in almost every way to the Spit V

What we actually know is that the A6M3 was superior to a tropicalized Spit V with Merlin 46 limited to 9lbs boost when all the tests were done below the Merlin 46's FTH.

A6M2 vs a Spitfire II using 12lbs boost lower altitudes might be a bit different. A6M2 vs Spit V with a Merlin 45 running 12-15lbs boost will certainly be different.

 

[Admiral Beez]

A6M2 vs Spit V with a Merlin 45 running 12-15lbs boost will certainly be different.

More so if the Darwin Zeros had the Spitfire V's armoured cockpit, radio and self sealing tanks.

 

[ThomasP]

The A6M2 had 1x 38 USgal fuselage tank (that weighed 22 lbs), plus 2x 51 USgal wing tank (that weighed 24 lbs each) for a total fuel load of 141 USgal. The tanks were non-SS and were welded aluminum with anti-slosh baffles. They were not integral to the structure (ie they were not a "wet wing" type) and they were designed to be replaceable.

The most common type of SSFT used on UK aircraft (Hurricane, Spitfire, Mosquito, Lancaster to name a few) for most of the war, was the CIMA type (manufactured by FPT and others). It was a .5" thick multi-ply laminate applied over the outside of a metal tank, weighing about .96 lbs/ft2.

The A6M2 fuel tanks were approximately the following size (I looked for accurate dimensions but did not find any, so I approximated from the cut-aways and blueprints I did find.)

The 38.0 USgal tank was about 1.36' x 1.5' x 2.5' which equals a volume of 5.1 ft^3 and a wall square footage of 21.8 ft^2
Each 51.5 USgal tank was about 1.00' x 2.2' x 3.2' which equals a volume of 6.9 ft^3 and a wall square footage of 24.9 ft^2

NOTE that 1 ft^3 = 7.48 USgal by volume

1 x 38.0 USgal 21.8 ft2 x .96 = 21 lbs added weight
1 x 51.5 USgal 24.9 ft2 x .96 = 24 lbs added weight
1 x 51.5 USgal 24.9 ft2 x .96 = 24 lbs added weight

The .5" thickness would also reduce the dimensions of the metal structure and the volume of the tank by an amount proportionate to the square footage of the tank walls, so:

1 x 38.0 USgal = 5.1 ft3 - 21.8 ft2 x .5" x 12"^2 / 12"^3 = 0.91 ft^3 yielding a reduction in volume of 6.8 USgal
1 x 51.5 USgal = 6.9 ft3 - 24.9 ft2 x .5" x 12"^2 / 12"^3 = 1.04 ft^3 yielding a reduction in volume of 7.8 USgal
1 x 51.5 USgal = 6.9 ft3 - 24.9 ft2 x .5" x 12"^2 / 12"^3 = 1.04 ft^3 yielding a reduction in volume of 7.8 USgal

The increase in weight due to the SSFT materials would be about 69 lbs and the decrease in fuel load would be 22.4 USgal.
Fitting the same amount of armor as the 1941 Spitfire carried would add about 150 lbs.
Adding a more capable radio such as the TR.1133 would add another 30 lbs or so.
Increase in weight due to the SSFT, armour, and radio, would be 69 + 150 + 30 = 249 lbs.
Decrease in weight due to reduction in fuel load would be 22.4 USgal x 6 lb/gal = 135 lbs.

Net change in TOGW would be 249 - 135 = +114 lbs.

So the increased TOGW would be 5335 + 249 - 135 = 5449 lbs, while the wing loading at combat weight would only increase by about 1.03 lb/ft^2.

Decrease in range would be significant, at a bit over 22.4 / 141 = 16% or about 200 miles, leaving a range of 1000 miles at 250 mph TAS/200 IAS (max economic cruise at 15,000 ft), with enough fuel for 20 minutes of combat (max power) and 30 minutes reserve (at best economic cruise).

In addition to the above weight increases you would probably have to strengthen the underlying metal structure of the fuel tanks. I do not know how much weight this would add to the above calculations, but I doubt it would be more than 50-60 lbs (That is just a guestimate on my part, as I am not familiar with the structure required to withstand the forces imposed on the tank by the impact and penetration of the projectiles).

The A6M3 had a TOGW of ~5500 lbs and according to the US, Australian, and UK tests, it was still ridiculously more maneuverable than the Allied fighters at low-medium speeds so I figure the same mods could be done to the A6M3 with little loss in combat effectiveness.

(I am doing this late at night so let me know if I made any errors. )

edit: The above 1000 mile range is predicated on the maximum range not being limited by the internal fuel load. The fuel load at TOGW would be 141 - 22.4 = 118.6 USgal internal plus the normal 87 USgal DT, for a total fuel load of 118.6 + 87 = ~205 USgal.

2nd edit: tyrodtom pointed out that I made an error in my original calculations by incorporating a multiplier of .5 in the added weight of the SSFT calculations. I have corrected the above calculations and all subsequent calculations/values in my later posts. Thank you tyrodtom.

 

[SaparotRob]

Math looks right to me .

 

[Admiral Beez]

In addition to the above weight increases you would probably have to strengthen the underlying metal structure of the fuel tanks.

Very informative, thanks. You bring up a good point on structural strength. If we're adding weight we'll need to also strengthen the undercarriage and much of weight bearing structure.

Some great pics of the Zero interior here Japanese Zero A6M Cockpit (Page 1) - Line.17QQ.com

 

[Glider]

What we actually know is that the A6M3 was superior to a tropicalized Spit V with Merlin 46 limited to 9lbs boost when all the tests were done below the Merlin 46's FTH.

A6M2 vs a Spitfire II using 12lbs boost lower altitudes might be a bit different. A6M2 vs Spit V with a Merlin 45 running 12-15lbs boost will certainly be different.

True to a point but if I remember correctly wasn't the A6M3 a rebuilt crashed example and if so, very unlikely to be pushed to the limit?

 

[SaparotRob]

If it's the Akutan Zero we're talking about, then you're correct.

 

[PAT303]

The A6M3 had a TOGW of ~5500 lbs and according to the US, Australian, and UK tests, it was still ridiculously more maneuverable than the Allied fighters at low-medium speeds so I figure the same mods could be done to the A6M3 with little loss in combat effectiveness.

The Zero could outturn anything below 180mph but allied pilots learnt that early on, if they stayed out of low speed turning fights the Zero lost that advantage, trouble for the Zero is if it got into a high speed fight it's controls stiffened over 300mph and locked up over 350 so just adding armor and SSFT is not going to improve it's all round fighting ability.

 

[ThomasP]

True, but some people feel that the main(?) problem with the A6M was the lack of armour and SSFT, making it more susceptible to being shot down for less damage received, leading to the loss of valuable skilled pilots. You are not going to solve the speed problem by adding armour and SSFT, but since the A6M was as fast/faster than the F4F, grossly outranged the F4F, and easily out-climbed and out-maneuvered the F4F, the added protection would eliminate the only significant advantage the F4F had.